Various types of recording liquids have been proposed for ball-point pens, felt-tipped pens, fountain pens, and ink jets. These recording liquids usually comprise dyes or pigments dissolved or dispersed in water or organic solvents.
Aqueous recording liquids comprising water-soluble dyes dissolved in water or a mixture of water and a small amount of an organic solvent are poor in writing performance on paper having high degrees of sizing due to a low penetrability thereinto. The image recorded with aqueous recording liquids is difficult to handle due to poor water resistance and sometimes undergoes reduction in definition due to blotting. In particular, tone sharpness of color images is apt to be impaired by blotting and mixing of recording liquids having different colors. In an attempt of overcoming these disadvantages associated with aqueous recording liquids, non-aqueous recording liquids, in which an oil-soluble dye is dissolved in a medium mainly comprising an organic solvent, are also proposed. However, none of oil-soluble dyes used in non-aqueous recording liquids so far proposed satisfies every or many of performance properties required, such as hue, absorbance, light-resistance, and solubility.